Electromagnetic relay



March 20, 1951 Q R. E. PROUTY 2,545,587

ELECTROMAGNETIC RELAY Filed Oct. 51, 1947 2 Sheets-Sheet 2 E0693 5 Prauy mmw M'V Patented Mar. 20, 1951 ELE ROMAGNET C E Robert E. Prouty, Logansport, Ind., assignor to Essex Wire. Corporation, Logansport, Ind., a

corporation of Michigan Application October 31, 1947', s 'e rial N q s a 15Olaims.

My invention relates; generally, to electromagnetic relays and it has particular relation to currentresponsive relays for starting fractional horsepower motors of the split phase type although it ma be used for other purposes.

Amon the objects of my invention are: To provide a series type relay for motor starting purposes and the like which will operate accurately on the current change in the main winding of a split phase motor between its initial energization. and a subsequent running condition; to construct such a relay with contacts for closing an energizing circuit for the starting winding on initial energization of the motor and arranging for these contacts to, open when the current flow through the motor decreases below the initial current inrush; to operate the contacts by an armature located within the winding of the relay that is positioned within a generally rectangular frame of magnetic material; to mount the armature for pivotal movement within a sleeve located within the winding; to actuate the contacts by an actuator pin extendin through the armature; to mount the. movable contact on a generally rectangular sprin that surrounds the winding and is anchored to the frame; to bias the armature by a similar spring also anchored to the frame; to position the springs so that they bear against the ends, of the actuator pin; and to provide for individually adjusting the biasing portions of the generally rectangular springs.

Other objects of my invention will, in part, be obvious and in part appear hereinafter.

My invention is disclosed in the embodiment thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appende claims.

For a more complete understanding ofthe nature and scope of my invention, reference, canbe had to the following detailed description, taken tfi ether with the accompanying drawings, in which:-

Figure 1 is a top plan View, at double, scale, of a relay constructed in accordance with my invention, an insulating housing being shown around the, operating mechanism of the relay;

Figure 2 is a view, in end elevation, of the relay shown in Figure 1 Figure 3 is a detail sectional view taken along the line 3-3 of Figure l;

Figure 4 is a detail" sectional view taken alon the line 44 of; Figure 1;

Figures 5, 6 and '7 are detail sectional views taken, respectively, along the lines 5'5, fi-6 and 'l --1- of Figure 3 Figure 8 is a perspective View of the operating mechanism-of the-relay; and

Figure 9 illustrates, diagrammatically, how the relay constructed as disclosed herein can be employed for starting a split phasetype of fractional horsepower; motor.

Referring; now particularly to Figures 1 and 2 of the drawings; it will be observed that the reference character'- ll) designates, generally a relay of' the electromagnetic type which is constructed in accordancewith my invention. For illustrative purposes the relay shown in these and succeeding Figures 3 through 8' is illustrated at double actual: scale of the relay which has been made and tested. This relay is particularly useful in connection with the starting of; split phase fractional horsepower motors-such as the motors used for operating electric refrigerators and the like. However, it will be understood that it can be used for other purposes as desired.

The relay 1-0 is contained in a case or housing N that is moulded of suitable insulating material such as a phenolic condensation product. The case or. housing H has integrally formed aperturedr foot port-ions l2 and is provided on the upper side with screw terminals I3, I4 and i5 to peri rit the necessary external connections to the motor and the line or energizing circuit. The case or; housing H is closed on the bottom side by a cover- I 6, Figure 3; of insulating material which maybe the same material as that of which the case or housing H- is formed. The cover it is held in place by suitable hollow rivets or eyelets l? which extend through it and through the foot portions l2, as illustrated.

Referring nowto. Figures 3 through 8 of the drawings, it will be observed that a generally rectangular frame 29 of magnetic material is provided for carrying magnetic flux and also to provide a mounting for the parts making up the relay construction. The frame 26 has an offset portion 2! at its right hand end which may be employed to provide a snap. action and for supporting an overload device to. be described hereinafter, such as. that shown in my copending applicatien Serial No. 783,411, filed October 31, 1947.

The generally, rectangular frame 26 has a centrally located window? izithin which is located a spool'23, Figure 5, of insulating material having end washers 24 also formed of insulating material and arranged to receive a winding 25 in the form of a series coil which is arranged to be connected in series with the run winding of the motor which is connected to be started by the relay IE1. The number of turns and the size of the wire forming the winding 25 depend, of course, upon the application of the relay In. As seen in Figures 4 and 6, the end washers 24 of the insulating spool 23 have notches (not shown) formed along their edges which lie adjacent the periphery of the window 22 whereby the spool may slidingly interlock with the frame 20 to support and hold the coil in place on the frame. While the relay ii! is described as a series type of relay it will be understood that it can be employed as a shunt type of relay with appropriate modification of the design of the winding 25. The winding 25 has leads 26 and 21 which extend therefrom. As shown in Figure 3, the lead 26 extends through the rectangular frame 26 and may be connected, as by solder 23, to the screw terminal H4. The lead 21 extends through an insulating sleeve 29 and may be connected by solder 3E1, Figure 1, to the screw terminal l3.

Again referring to Figure 5, within the spool 23 of insulation there is located a sleeve 33 of non-magnetic material such as brass. The sleeve 33 has a generally rectangular configuration with extensions 34 projecting beyond the spool 23 which have ears 35 extending at right angles thereto to permit fastening to the frame 20 as by solder 36, Figure 3. In this manner the nonmagnetic sleeve 33 is held in fixed location with respect to the frame 26. vided for supporting an armature 3'! that is in the form of a bar of magnetic material having a generally rectangular cross section. The armature 3! projects beyond the ends of the winding 25 and is pivotally mounted within the same by a pivot pin 38 which extends through the armature 3'! and is carried by the sleeve 33. As will appear hereinafter, the armature 3'! is biased by a spring member away from a position of minimum reluctance with the frame 20. When the winding 25 is energized, the armature 3'! is caused to move against this biasing force toward a position of minimum reluctance with respect to the frame 2E3. t is this movement of the armature 3? from one position to another in response to energization of the winding 25 that controls the functioning of the relay l0. As stated, the armature 31 projects beyond the ends of the winding 25. The portion 39 thereof projects beyond the left hand end while the portion it projects be-- yond the right hand end. It is the latter projecting end 40 of the armature 3! that is referred to in certain of the claims with reference to the definition of the armature 3'! having a portion which extends beyond the winding 25. The extended portion 39 of the armature 31 is provided to complete the magnetic circuit to the left hand end of the frame 20.

The end portion 38 of the armature 37 carries an actuator pin H that is formed of non-magnetic material such as aluminum. It will be observed that this pin extends at right angles to the armature 31 and that it is employed for controlling the operation of the contacts to be described presently. A generally rectangular spring 42 of beryllium copper or similar material engages one end of the actuator pin 4! and serves to bias it and the armature 31 away from the The sleeve 33 is pro- 4 position of minimum reluctance with the frame 20.

The armature 37 is actuated with a snap action against the biasing force of the spring 42 on energization of the winding 25 because of the pro vision of the offset portion 2! of the frame 20 which provides the core for the electromagnetic relay. In Figure 3 it will be noted that the rec tangular spring d2, acting through the actuator pin 4|, urges the armature 37 to a position out of alignment with the main portion of the frame 20. On energization of the winding 25 the armature 3'! is moved to a position of minimum reluctance which is somewhat past a position of alignment with the main portion of the frame 29 and inclined toward its offset portion 2 i. As the armature 3i approaches this position it is moved, in effect, with a snap action as a result of the decreasing distance between its end as and the offset portion 2! of theframe 2i] and the operation of the inverse square law of magnetic attraction.

The generally rectangular spring 42 is anchored at its left hand end to a generally U-shaped bracket 43 that preferably is formed of brass or similar material. One arm of the U-shaped bracket 43 is provided with ears 34, Figure '7, which are fastened to the frame 2E3. The generally rectangular spring 42 is secured to the other arm 55 of the bracket 53 by rivets 46, the arm it? being intermediate the ears 443 to provide a resilient arched construction therebetween. An adjusting screw i? is threaded through arm 45 of the bracket 33 so that its inner end bears against the frame 20. By moving the adjusting screw t? in one direction or the other it is possible to adjust the biasing force that is applied by the generally rectangular spring 42 to the actuator pin 4 I. Since the bracket 13 is formed of resilient material, the opening between the arms 44 and :35 thereof is varied depending upon the position of the screw 4?. In this manner the anchor end of the spring 32 can be adjusted to vary its biasing force.

The relay construction disclosed herein is arranged to control the relative movement of contacts 59 and 5! which preferably are in the form of silver buttons. For the particular application of the relay It disclosed herein, the contacts 50 and 5! are arranged to be normally in the open position. Obviously, if the occasion warrants, the contacts 59 and 5! can be arranged to be normally in the closed position and to be opened upon energization of the winding 25. However, as disclosed herein, the contacts 55 and M are arranged to be closed when the winding 25 is energized.

It will be observed in Figure 8 that the contact 5| is stationary and that it is carried by conductor strip 52 which is secured to and carried by a bracket 53 of insulating material. The bracket 53 may be secured to the frame 29 by rivets 54. A lead 55 extends from the conductor strip 52 to the screw terminal E5 to which it may be secured by solder as indicated at 55 in Figure 1. It will be understood that the soldering of the leads 25, 21 and 55 to the respective screw terminals I l, 13 and !5, serves to hold. the frame 28 of the relay and parts mounted thereon securely in position within the case or housing I I.

The movable contact button 5% is carried by a generally rectangular spring 56 which is shaped similar to the spring :12 and like it surrounds the winding 25. Preferably the spring 56 is formed of beryllium copper in order to provide the desired resiliency: and electrical. conductivity; The;

spring. 56- is anchored tov the frame 28inthe. same; manner that the Spring. 42 is anchored. thereto. It. Will. be noted that the side. of the spring: 56

opposite from the contact button. 50 is secured.

to. one arm of a generally U-shapedbracket 58 which, like the bracket 43, can be formedof brass or other similar resilient material. The rectangular spring 55 may be secured to the arm 51 of the bracket 58 by rivets 59,. Figure 6. The other arm of the bracket 58 is provided with cars 60 which are fastened. to the. frame, 20 by hollow rivets 8| which also serve to hold. the ears 44 of. the bracket 43 in position thereon. The biasing force of the generally rectangular spring 56' can be changed. by an adjusting screw 62 which is. threaded through the spring 56 andthrouglrthe arm 51 of the bracket 58. The inner end. of the screw 62 bears against the adjacent surfaceof the frame 25.. Since the bracket 58 is formed of resilient material its arms are moved apart or are brought together as the position of the screw is changed.

It will be understood that the adjusting screws 41 and 62 are positioned so that the biasing force applied by the generally rectangular spring 42' to the actuator pin 4t exceeds. the biasing force applied thereto by the generally rectangular spring 56 which carries the movable contact button 58. However, the adjusting screw 52 is positioned so that the spring 56 willmove the contact button 50 into contact engagement with the stationary contact button 5| under the required contact pressure when the winding 25 is energized and the armature 31 is attracted toward its position of minimum reluctance with the frame 20. It will be understood that when the winding 25 is energized and the armature 31 is attracted. as described, the actuator pin 4! moves the spring 42 away from the frame 25 thereby permitting the spring 56 to follow the actuator pin 4i! until the contact button 50 engages the stationary contact button 5|. The contact pressure applied between the contact buttons 58 and 5| therefore. is solely a function of the biasing force exerted by the generally rectangular spring 56.

In Figure 9 of the drawings, the manner. in which the relay can be connected to control the starting of a motor is shown. It will be noted that the screw terminal I5, which is connected to the stationary contact button 5|, is connected by a conductor 55 to a start winding 66 of a split phase fractional horsepower motor indicated, generally, at 67. The motor 67 may have a squirrel cage rotor 68 and a run winding 59. A conductor 19 interconnects the screw terminal [3 and the run winding 69 while a conductor H interconnects the common connection between the.

windings 66 and G9 and a line terminal 12. A conductor l3 interconnects the remaining screw terminal l4 and another line terminal. 14.

Assuming that the motor 61 is a conventional quarter horsepower motor, when the line terminals l2 and T4 are energized, as by connection thereto of a suitable 60 cycle 110 volt alternating current source, current will flow from the line terminal 12 through the run winding 69, relay winding 25 to the other line terminal 14. This current may be in excess of 20 amperes and is sufficient to cause the winding 25 to attract the armature 31 toward the position of minimum re. luctance whereupon the contacts. 55 and. 5.l are closed. Current then also flows through the.

start'winding 66 and. causes the rotor 68 to rotate until at a speed of about 1500 R. P..M.. the current drawn. by the; run. winding 69 drops to a value. low enough to allowthe. armature 31 to be.

moved. away from the position of minimum. reluctance by the spring 42'. llhis current may be of. the order of 12- amperes. When this occurs the; contacts 50: and 5 lare. separated and the start winding 66 is deenergized. The rotor 58 continuestooperate solely as a. result of the energization of the run winding 69 the current flow through which drops to about 4 amperes. The relay construction is such that it has a. closeoperating: differential with about 15 per cent change in current to. permit the armature 31 to move away from. the position of. minimum reluctance after the. contacts 50' and 5t have been closed as a result of the initial current inrush.

Since certain changes; can be made in the fore.-

going construction and. diiferent; embodiments of the invention, can be: made without departing. from the spirit and scope thereof, it is intended that allmatter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not ina limiting sense.

I claim as my invention:

1. A relay comprising, in combination, a generally rectangular flat continuous frame of platelike magnetic material, a spool of insulating ma.- terial mounted within an opening insaid frame, a winding wound about said. spool and within said opening in said frame, an armature pivotally mounted. within said spool, an actuator carried by said armature, interlocking means between said spool and said frame, resilient means biasing said armature and actuator, and a pair of cooperating contacts movable relative to each other as a resultof. movement of said actuator against the.

biasing force of said resilient means on energization. of. said. winding.

2. A relay comprising, in combination, a generally rectangular fiat continuous frame of platelike magnetic material, an insulating spool mounted within an opening in said frame, a winding mounted on said spool within said frame, a sleeve of non-magnetic material within said winding. andv spool,v interlocking means between said spool and said frame, an armature pivotally mounted within said sleeve, an actuator carried by said armature, resilient means biasing said actuator, and a pair'of cooperating contacts movable relative to each other as a result of movcment of said actuator against the iasing force of said resilient means on energization of said winding.

3.. A. relay comprising, in combination, a generally rectangularfiat continuous frame of platelike magnetic material, a hollow insulating spool mounted within a central opening in said frame, a. winding supported by said spool within said frame, a sleeve of nonmagnetic material within said winding and spool, interlocking notch means between said spool and frame for mounting said winding, sleeve, andspool to said frame; an armaturev pivotally mounted within said sleeve, resilient means biasing said armature, and a pair of cooperating contacts movable relative to each other as a result of movement of said armature against the biasing force of said resilient means on energization of said winding.

4. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, an armature within said winding and extending beyond one end thereof, resilient means biasing said armature away from a position of minimum. reluctance with said. frame, a pair of cooperating contacts movable relative to each other as a result of movement of said armature toward said position of minimum reluctance on energization of said winding, and a generally rectangular spring surrounding said winding and carrying one of said contacts and anchored to said frame at the other end of said winding.

5. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, an armature within said winding and extending beyond one end thereof, resilient means biasing said armature away from a position of minimum reluctance with said frame, a pair of cooperating contacts movable relative to each other as a result of movement of said armature toward said position of minimum reluctance on energization of said winding, a generally rectangular spring surrounding said winding and carrying one of said contacts and anchored to said frame at the other end of said winding, and means for adjusting the biasing force of said rectangular spring at the anchor end thereof.

6. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, an armature within said winding and extending beyond one end thereof, resilient means biasing said armature away from a position of minimum reluctance with said frame, a pair of cooperating contacts movable relative to each other as a result of movement of said armature toward said position of minimum reluctance on energization of said winding, an adjusting bracket fastened to said frame at the other end of said winding, a generally rectangular spring surrounding said winding and carrying one of said contacts and fastened to said bracket, and a screw threaded in said bracket and bearing against said frame for adjusting the biasing force of said spring 7. A relay comprising, in combination,- a generally rectangular frame of magnetic material, a winding within said frame, an armature within said winding and extending beyond one end thereof, a generally rectangular spring surrounding said winding and anchored to said frame at the other end of said winding for biasing said armature away from a position of minimum reluctance with said frame, a pair of cooperating contacts movable relative to each other as a result of movement of said armature toward said position of minimum reluctance on energization of said winding, and a generally rectangular spring surrounding said winding and carrying one of said contacts and anchored to said frame at said other end of said winding.

8. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, an armature within said winding and extending beyond one end thereof, a generally rectangular spring surrounding said winding and anchored to said frame at the other end of said winding for biasing said armature away from a position of minimum reluctance with said frame, a pair of cooperating contacts movable relative to each other as a result of movement of said armature toward said position of minimum reluctance on energization of said winding, a generally rectangular spring surrounding said winding and carrying one of said contacts and anchored to said frame at said other end of said winding, and means for adjust-' ing individually the biasing forces of said rectangular springs at the anchor ends thereof.

9. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, an armature within said winding and extending beyond one end thereof, an adjusting bracket fastened to one side of said frame at the other end of said winding, a generally rectangular spring surrounding said winding and fastened to said bracket for biasing said armature away from a position of minimum reluctance with said frame, a pair of cooperating contacts movable relative to each other as a result of movement of said armature toward said position of minimum reluctance on energization of said winding, an adjusting bracket fastened to the other side of said frame at said other end of said winding, a generally rectangular spring surrounding said winding and fastened to the second named bracket for carrying one of said contacts, and a screw threaded into each of said brackets and bearing against said frame for adjusting individually the biasing forces of said rectangular springs.

10. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, an armature within said winding and extending beyond one end thereof, an actuator carried by the extended portion of said armature, resilient means biasing said actuator, a pair of cooperating contacts movable relative to each other as a result of movement of said actuator against the biasing force of said resilient means on energization of said winding, and a generally rectangular spring surrounding said winding and carrying one of said contacts and anchored to said frame at the other end of said winding.

11. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, a sleeve of non-magnetic material within said winding, an armature pivotally mounted on said sleeve and extending beyond one end of said winding, resilient means biasing said armature away from a position of minimum reluctance with said frame, a pair of cooperating contacts movable relative to each other as a result of movement of said armature on energization of said winding, and a generally rectangular spring surrounding said winding and carrying one of said contacts and anchored to said frame at the other end of said winding.

12. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, a sleeve of non-magnetic material within said winding, an armature pivotally mounted on said sleeve and extending beyond one end of said winding, an actuator pin of non-magnetic material extending transversely of and secured to the extended portion of said armature, resilient means engaging and biasing said actuator pin at one end, a pair of cooperating contacts movable relative to each other as a result of movement of said actuator pin against the biasing force of said resilient means on energization of said winding; and a generally rectangular spring surrounding said winding, anchored to said frame at the other end of said Winding, carrying one of said contacts, and engaging the other end of said actuator pin.

13. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, a sleeve of non-magnetic material within said winding, an armature pivotally mounted on said sleeve and extending beyond one end of said winding, an actuator pin of non-magnetic material extending transversely of and secured to the extended portion of said armature, a generally rectangular spring surrounding said Winding and anchored to said frame at the other end of said winding for engaging and biasing said actuator pin at one end, a pair of cooperating contacts movable relativ to each other as a result of movement of said actuator pin against the biasing force of said spring on energization of said winding; and a generally rectangular spring surrounding said winding, anchored to said frame at said other end of said winding, carrying one of said contacts, and engaging the other end of said actuator pin.

14. A relay comprising, in combination, a generally rectangular frame of magnetic material, a winding within said frame, a sleeve of non-magnetic material within said winding, an armature pivotally mounted on said sleeve and extending beyond one end of said winding, an actuator pin of non-magnetic material extending transversely of and secured to the extended portion of said armature, a generally rectangular spring surrounding said winding and anchored to said frame at the other end of said winding for engaging and biasing said actuator pin at one end,

a pair of cooperating contacts movable relative to each other as a result of movement of said actuator pin against the biasing force of said spring on energization of said winding, a bracket of insulating material secured to said frame near said one end of said winding for carrying one of said contacts; and a generally rectangular spring surrounding said winding, anchored to said frame at said other end of said winding, carrying the other of said contacts, and engaging the other end of said actuator pin.

15. A relay comprising, in combination, a generally rectangular fiat continuous frame of platelike magnetic material having one side offset relative to the other sides, a winding within said frame, an armature rockably mounted within said winding and extending between said offset side and the opposite side of said frame, a spring urging said armature away from a position of minimum reluctance between said ofiset side and the opposite side of said frame whereby snap action of said armature on energization or deenergization of said winding is effected, and a pair of cooperating contacts movable relative to each other as a result of operation of said armature.

ROBERT E. PROUTY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,876,295 Hofgaard Sept. 6, 1932 2,072,578 Barrett et a1 Mar. 2, 1937 2,193,516 Laing Mar. 12, 1940 2,344,654 Stong Mar. 21, 1944 2,438,609 Juhasz Mar. 30, 1948 FOREIGN PATENTS Number Country Date 71,322 Austria Mar. 10, 1916 

